Translation table sharing

Abstract

In some embodiments, there is provided performing a table scan semi-join on a plurality of second value second identifier of the second table by scanning a plurality of second value identifiers that have been filtered by the translated plurality of first value identifiers and reading one or more filtered second value identifiers of the second table, providing the one or more filtered second value identifiers of the second table as a probe into the hash table including the translated plurality of first value identifiers, and outputting one or more matching rows corresponding to matching value identifiers for matching values in the first table and the second table. Related systems, methods, and articles of manufacture are also disclosed.

What is claimed is: 
     
         1 . A computer-implemented method comprising:
 detecting, in a query execution, a join of a first table and a second table; and   in response to the detecting the join, optimizing the query execution by at least scanning a plurality of first value identifiers from the first table,
 translating the plurality of first value identifiers into a value identifiers domain of the second table to form a shared translation table, 
 building a hash table using the translated plurality of first value identifiers, 
 performing a table scan semi-join on a plurality of second value second identifier of the second table by scanning a plurality of second value identifiers that have been filtered by the translated plurality of first value identifiers and reading one or more filtered second value identifiers of the second table, 
 providing the one or more filtered second value identifiers of the second table as a probe into the hash table including the translated plurality of first value identifiers, and 
 outputting one or more matching rows corresponding to matching value identifiers for matching values in the first table and the second table. 
   
     
     
         2 . The computer-implemented method of  claim 1 , wherein a database execution engine detects the join of the first table and the second table. 
     
     
         3 . The computer-implemented method of  claim 1 , wherein the join comprises an inner join of a first column of the first table and a second column of the second table. 
     
     
         4 . The computer-implemented method of  claim 3 , wherein the first column includes the plurality of first value identifiers, and wherein the second column includes the plurality of second value identifiers. 
     
     
         5 . The computer-implemented method of  claim 1 , wherein the translating comprises generating the shared translation table based a first dictionary of the plurality of first value identifiers and a second dictionary of the plurality of second value identifiers. 
     
     
         6 . The computer-implemented method of  claim 1 , wherein the building of the hash table comprises inserting the translated plurality of first value identifiers into the hash table. 
     
     
         7 . The computer-implemented method of  claim 1 , wherein the plurality of second value identifiers are filtered by a filter, wherein the filter detects whether or not the translated plurality of first value identifiers in the plurality of second value identifiers. 
     
     
         8 . The computer-implemented method of  claim 7 , wherein the filter comprises a bloom filter. 
     
     
         9 . A system comprising:
 at least one processor;   at least one memory including program code which when executed by the at least one processor causes operations comprising:
 detecting, in a query execution, a join of a first table and a second table; and 
 in response to the detecting the join, optimizing the query execution by at least scanning a plurality of first value identifiers from the first table, 
 translating the plurality of first value identifiers into a value identifiers domain of the second table to form a shared translation table, 
 building a hash table using the translated plurality of first value identifiers, 
 performing a table scan semi-join on a plurality of second value second identifier of the second table by scanning a plurality of second value identifiers that have been filtered by the translated plurality of first value identifiers and reading one or more filtered second value identifiers of the second table, 
 providing the one or more filtered second value identifiers of the second table as a probe into the hash table including the translated plurality of first value identifiers, and 
 outputting one or more matching rows corresponding to matching value identifiers for matching values in the first table and the second table. 
   
     
     
         10 . The system of  claim 9 , wherein a database execution engine detects the join of the first table and the second table. 
     
     
         11 . The system of  claim 9 , wherein the join comprises an inner join of a first column of the first table and a second column of the second table. 
     
     
         12 . The system of  claim 11 , wherein the first column includes the plurality of first value identifiers, and wherein the second column includes the plurality of second value identifiers. 
     
     
         13 . The system of  claim 9 , wherein the translating comprises generating the shared translation table based a first dictionary of the plurality of first value identifiers and a second dictionary of the plurality of second value identifiers. 
     
     
         14 . The system of  claim 9 , wherein the building of the hash table comprises inserting the translated plurality of first value identifiers into the hash table. 
     
     
         15 . The system of  claim 9 , wherein the plurality of second value identifiers are filtered by a filter, wherein the filter detects whether or not the translated plurality of first value identifiers in the plurality of second value identifiers. 
     
     
         16 . The system of  claim 15 , wherein the filter comprises a bloom filter. 
     
     
         17 . A non-transitory computer-readable storage medium including program code which when executed by at least one processor causes operations comprising:
 detecting, in a query execution, a join of a first table and a second table; and   in response to the detecting the join, optimizing the query execution by at least scanning a plurality of first value identifiers from the first table,
 translating the plurality of first value identifiers into a value identifiers domain of the second table to form a shared translation table, 
 building a hash table using the translated plurality of first value identifiers, 
 performing a table scan semi-join on a plurality of second value second identifier of the second table by scanning a plurality of second value identifiers that have been filtered by the translated plurality of first value identifiers and reading one or more filtered second value identifiers of the second table, 
 providing the one or more filtered second value identifiers of the second table as a probe into the hash table including the translated plurality of first value identifiers, and 
 outputting one or more matching rows corresponding to matching value identifiers for matching values in the first table and the second table. 
   
     
     
         18 . The non-transitory computer-readable storage medium of  claim 17 , wherein a database execution engine detects the join of the first table and the second table. 
     
     
         19 . The non-transitory computer-readable storage medium of  claim 17 , wherein the join comprises an inner join of a first column of the first table and a second column of the second table. 
     
     
         20 . The non-transitory computer-readable storage medium of  claim 19 , wherein the first column includes the plurality of first value identifiers, and wherein the second column includes the plurality of second value identifiers.